Memory circuits have been used in various applications. Conventionally, memory circuits can include dynamic random access memory (DRAM) and static random access memory (SRAM) circuits. To enhance accessing speeds of memory, synchronous dynamic random access memory (SDRAM) has been provided. Conventionally, SDRAM has a synchronous interface. By using the synchronous interface, SDRAM waits for a clock signal prior to responding to control inputs so as to synchronize with buses of computer systems. To further enhance speeds of SDRAM, a double-data-rate (DDR) interface has been developed and applied in industry. Later, DDR2, DDR3, and DDR4 were different updated versions of DDR SDRAM.